SEATTLE (Reuters) - An estimated 700,000 Seattle Seahawks fans braved sub-freezing temperatures to celebrate the football team's first Super Bowl title at a parade that wound through the city's downtown on Wednesday.

The Seahawks trounced the usually high-scoring Denver Broncos, 43-8, on Sunday to win their first National Football League championship in franchise history.

It was a particularly sweet triumph for a city whose previous major professional men's sports team championship came a generation ago, when the SuperSonics captured the National Basketball Association's crown in 1979. That team left for Oklahoma City in 2008.

Kicking off before noon and running for about two hours, the parade was slowed by the larger-than-anticipated crowd - with some fans perched in trees and atop pillars - that transformed downtown Seattle into a sea of blue and green, the team's colors. Police estimated the crowd at 700,000 strong.

"I've never seen a community come together like this," said Tyler Olsen, 29, a Seattle-area high school math teacher who took the day off to watch the procession. "It's an overwhelming sense of joy."

Shortly after the parade commenced, the crowd burst into an ear-splitting roar as part of a statewide "moment of LOUDNESS" proclaimed a day earlier by Governor Jay Inslee.

In a nod to the team's fans, collectively known as the "12th Man" for their opponent-rattling rumbling during home games, the organized screaming occurred at 12:12 p.m.

As fans cheered them along the route, players and coaches danced and waved from slow-moving amphibious World War Two-era Duck vehicles normally used by tourists, with star running back Marshawn Lynch throwing his preferred candy, Skittles, into the crowd.

The procession culminated at CenturyLink Field - the Seahawks' home stadium - where the team has lost only once during the past two years, and where season-ticket holders were treated to a post-parade victory celebration.

With traffic snarled and public transportation backed up by those heading into the city, not everyone planning to attend the parade made it.

Patti Tinsley, 43, brought her two children, ages 5 and 7, to the light-rail train station in the Seattle suburb of SeaTac. But after waiting over an hour in a line that snaked around the block, she decided to return home - though her spirits remained high.

But with over 13,500 students absent from Seattle's public schools - at least 10,000 more than normal, a district spokeswoman said - it was clear that many others had not only made it to the parade but were treating the day as an unofficial holiday.

A day earlier, Seattle Public Schools Superintendent Jose Banda said it was up to individual principals whether students' absences would be excused.

It was a reversal from his position on Monday, when he said that students would not be excused in spite of a suggestion from Seahawks Head Coach Pete Carroll that they get the day off.

Carroll received a phone call on Tuesday from President Barack Obama, who commended the coach on the team's "decisive victory" and said he looked forward to greeting them at the White House in the coming months, according to a White House statement.